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Perceptual priming in schizophrenia evaluated by word fragment and word stem completion

Implicit memory seems to be preserved in schizophrenia as a whole, but dissociations between conceptual and perceptual tasks and between accuracy and reaction time measures have appeared. The present research has revealed some methodological limitations in many studies to date that are focused on the study of perceptual implicit memory in schizophrenic patients using accuracy measures. The review of these studies revealed that limitations are related to an inadequate definition of performance and priming measures, a lack of control over the characteristics of the stimuli, and the absence of information on the experimental procedures used in data collection. Moreover, the task used in these studies is word stem completion, a task that makes use of perceptual and conceptual processes. In the experiment reported here we use a pure perceptual implicit task and stimuli selected from a normative database to measure perceptual implicit memory in schizophrenic patients. Their performance was compared with that of normal participants. Thirty-two schizophrenic patients and 30 healthy control participants were administered a word fragment completion task. Direct comparison between the two groups yielded similar results in priming, suggesting that perceptual implicit memory is preserved in schizophrenia.

Relationships between electrodermal activity and symptomatology in schizophrenia.

The present report studies the differences between schizophrenic responders and nonresponders within the different symptomatologic groups of the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS). The relationship between the different electrodermal activity parameters and the scores on the scales was also analyzed. The results showed that nonresponders had negative symptoms. In addition negative symptoms registered a general fall in all electrodermal-activity parameters.

The effect of associative strength on semantic priming in schizophrenia

The present research was designed to investigate the pattern of semantic priming in schizophrenia as a function of strength of association (or semantic distance between concepts in the semantic network). Thirty schizophrenia patients, without formal thought disorder, and twenty-nine healthy controls participated in a lexical decision task in which prime-target associative strength (strong, weak and not related) and stimulus-onset asynchrony (SOA: 250ms and 750ms) were manipulated. Patients and controls showed the same associative strength effect on RTs. In the short SOA condition priming effects were obtained for both strong and weak prime-target associative conditions. However in the long SOA priming was only significant for strongly associated pairs. This pattern of priming effects was similar in both groups, with higher priming on the short SOA and strong association conditions. Altogether results suggest that automatic semantic spreading activation is unimpaired in schizophrenia patients without formal thought disorder. These results are in line with the general evidence of impaired implicit priming observed only in patients with formal thought disorder. At the same time patients use context as controls to facilitate word processing. Finally, these findings evidence that, prime-target associative strength could moderate results in studies of semantic memory deficits in schizophrenia.

Effectiveness of the cognitive differentiation program of the integrated psychological therapy: group versus individual treatment.

Abstract The aim of the current pilot study was to compare two strategies in the application of the cognitive differentiation program of Integrated Psychological Therapy for people with schizophrenia. Twenty-six outpatients were randomly assigned to the application of the program in group sessions (CDg), or to its application in individualized sessions (CDi). The program provides cognitive exercises to promote better performance in cognition, and both groups of participants completed the same number of exercises following the same number of sessions per week. Outcomes were assessed on neuropsychological measures of attention, executive functioning and everyday memory, and everyday functioning. Effect sizes showed the absence of effects in everyday memory and social functioning, higher improvements in the CDi group in attention, and a higher improvement in the CDg condition in executive functioning. The results suggest that the program application model could be individualized, depending on patient-specific cognitive deficits.